Organic Adsorption Capacity of Aluminum for Potential Mars Sample Return Contamination Analysis
Abstract
The NASA Mars 2020 rover will sample martian rock and regolith as it searches for biosignatures and chemical potential for life. Possible contamination of martian samples by Earth-derived organic and inorganic materials poses a challenge to the ultimate goal of determining whether features detected within samples are of martian origin. To address this issue, Mars 2020 will implement a contamination knowledge strategy that includes "witness blanks": special sample tubes that contain multiple "getter" materials designed to witness any ambient contamination in the environment during sampling events on Mars. One getter material being considered for use inside witness tubes is aluminum foil. Here we present data from a series of experiments to evaluate the capacity of aluminum foil to adsorb organics and release them by solvent extraction. Strips of clean aluminum foil were suspended in closed vials containing 0.15 mg of pyrene and heated to 50°C to provide a bounding case for ambient pyrene concentration. Another set of foil strips in vials was stored at -20°C to better simulate martian conditions. After ten weeks, these foil strips were exposed to pyrene at additive 15 minute increments to test the time dependence of pyrene adsorption at -20°C. Foil strips were removed from vials and subjected to solvent extraction gas chromatography mass spectrometry. Preliminary results suggest that the pyrene adsorption capacity of aluminum at 50°C is 1-10 ng/cm2 after 24 hours. Further research will test the adsorption capacity of aluminum at varying temperatures, varying times, and varying organic compositions.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2017
- Bibcode:
- 2017AGUFM.P41B2833S
- Keywords:
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- 0424 Biosignatures and proxies;
- BIOGEOSCIENCES;
- 0448 Geomicrobiology;
- BIOGEOSCIENCES;
- 0463 Microbe/mineral interactions;
- BIOGEOSCIENCES;
- 5215 Origin of life;
- PLANETARY SCIENCES: ASTROBIOLOGY